condition mean min max ZT0-3 3.249033333333333 2.5653699999999997 4.139835 ZT4-7 3.1588000000000003 3.1588000000000003 3.1588000000000003 ZT8-11 4.91244 4.91244 4.91244 ZT12-15 8.1709475 7.987435 8.35446 ZT16-19 8.5547 8.5547 8.5547 ZT20-23 6.02506 6.02506 6.02506